Outcome of vitreous surgery and the balance between vascular endothelial growth factor and endostatin

PURPOSE. To predict the results of vitreous surgery in patients with proliferative diabetic retinopathy (PDR), the correlation between vitreous fluid levels of vascular endothelial growth factor (VEGF) or endostatin and the postoperative outcome was investigated. METHODS. VEGF and endostatin levels in vitreous fluid specimens obtained during vitreous surgery were measured by enzyme-linked immunosorbent assay. Expression of VEGF and endostatin in epiretinal membranes was assessed immunohistochemically. Patients were prospectively followed up for 6 months. RESULTS. No improvement and/or progression of PDR was seen in 11 (25%) of 44 eyes (progression group). The vitreous fluid level of VEGF was significantly higher in the progression group than in the regression group (P = 0.0023). Conversely, the vitreous fluid level of endostatin was significantly higher in the regression group than in the progression group (P = 0.0299). Eyes with a high vitreous fluid level of VEGF and a low endostatin level had a significantly greater risk of progression of PDR after vitreous surgery than did eyes with low VEGF and high endostatin levels (odds ratio = 10.00, P = 0.047). VEGF and endostatin were detected immunohistochemically in the fibrovascular epiretinal membranes resected from the subjects. CONCLUSIONS. In this study both VEGF and endostatin were expressed in eyes with PDR. VEGF and endostatin levels in the vitreous fluid correlated with the outcome of vitreous surgery for PDR. Therefore, the outcome of PDR surgery can probably be predicted by measuring cytokines and/or growth factors in the vitreous fluid, with VEGF and endostatin being good candidates.